Breeding climate-resilient tomatoes: New approaches and challenges

A changing climate requires breeding for crop productivity under increasingly variable environments, including limited fresh water supplies in arid agricultural regions. Breeding crops for tolerance to water stress and increased water use efficiency would improve production sustainability by requiring less water for a given level of yield. Cultivated tomato (Solanum lycopersicum) is an economically important vegetable crop but it’s susceptible to abiotic stresses, including restricted water. In contrast, a wild tomato species (S. habrochaites) is highly tolerant to abiotic stresses. Breeding lines containing introgressions from S. habrochaites are being used in field experiments under restricted irrigation to determine the genetic basis of water stress tolerance-related traits and the effects of slow-onset water stress on plant traits, fruit quality and yield (productivity). The breeding lines will also be employed in a new multiyear project to evaluate an in-field, high-throughput phenotyping platform (HTPP) developed at UC Davis for assessing important fruit and plant traits in vegetable crops. The HTPP platform is designed to reduce the phenotyping bottleneck in breeding. HTPP measurements on tomato and pepper breeding lines will be compared with breeders’ manual trait phenotyping methods to assess the ability of HTPP to efficiently identify superior performing lines.